He has 8 positives, 3 neutrals, and now your transaction.
I personally would think a negative would be warranted but a neutral would also be acceptable.
I may ask staff if they think restrictions need to be placed on his account.
He's showing 100% because the neutrals count as 100%.
And the two most recent positives have "neutralish" undertones to them. The biggest problem that I see here is that unless you click the profile (which many people don't), all you will see is 100%, and assume that all is well. I've seen staff say before that incidents like this don't generally qualify for a negative, but I guess the question is whether a pattern of problems, even if none individually would warrant a negative, can be taken into account.